The present invention relates generally to intelligent network systems for providing communications services, and specifically, to a novel method and apparatus for supporting Virtual network (xe2x80x9cVnetxe2x80x9d) and Asynchronous Transfer Mode (xe2x80x9cATMxe2x80x9d) communications services in an intelligent network.
In communications networks comprising circuit-switched, packet-switched and/or frame relay communications technology, virtual private networks have been established as a measure to provide voice and data communications services at reduced costs, e.g., for a corporate enterprise. In such networks, communications is enabled between subscribing members of the VPN, with such subscribing members typically comprising corporate employees or preferred corporate customers at different locations throughout the United States and internationally.
In some instances, VPNs are overlayed onto the circuit-switched, e.g., public switched telephone network (PSTN), however, increasingly, are implemented over wide area networks implementing frame relay and/or packet-switched technologies. For example, packet-switched Asynchronous Transfer Mode (ATM) technology enables a carrier to provide integrated data, video, and voice services over a single network. In accordance with standard ATM technology, a shared ATM network 10, such as shown in FIG. 1, transfers and routes video, data, and voice traffic in 53 byte fixed-length packets from a source 12 to a destination 15 over a series of ATM switches 20a-g and interconnected links. The capability of carrying multi-media traffic on a single network makes ATM the preferred technology for B-ISDN services. The Asynchronous Transfer Mode protocol is connection-oriented, and traffic for an ATM xe2x80x9ccallxe2x80x9d is routed as cells over a virtual connection that extends from the source to the destination.
As known, a virtual connection is comprised of Virtual Channels (VC) and Virtual Paths (VP) in a multiplexing hierarchy. A physical transmission system is partitioned into multiple VCs and VPs, with some being designated for customer traffic (bearer channels) and some being designated for signaling. A VC is identified by a Virtual Channel Identifier (VCI), and a VP is identified by a Virtual Path Identifier (VPI). Prior to transmitting traffic over a bearer channel, the ATM network sets up an ATM call with signaling messages over a signaling channel. First, a setup message containing a Source Address, representing the location of the call originator, and a Destination Address, representing the location of the call recipient, is received and processed by an originating ATM switch, e.g., switch 20a. The originating ATM switch routes the setup message to a terminating ATM switch, e.g., switch 20f, via zero or more intermediate switches, in which the terminating ATM switch 20f serves the destination address (xe2x80x9cDAxe2x80x9d). Each ATM switch processes the setup message to ensure that it recognizes the DA and can route the call.
From each switch""s processing of the setup message, a virtual connection is established from source to destination to transport the customer traffic as cells over bearer channels. A virtual path or channel connection (VPC or VCC) refers to one or more concatenated links, one of which is depicted as link 25 shown in FIG. 1 connecting two ATM switches. A VP or VC link is defined as the transport between a point at which a VPI/VCI is assigned and a point at which a VPI/VCI is removed or translated. Specifically, at the inbound port of a switch, the VCI/VPI is used to determine the outbound port. The cell is then switched to an outboard port of the switch where a VCI/VPI is assigned to the cell. The cell is then transported to the next switch. Thus, a connection (VCC/VPC) extends from the source, usually the inbound port on the originating ATM switch, to the destination, usually the outbound port on the terminating ATM switch.
The signaling protocol is defined in ATM standards according to network interfaces. The ATM Forum has defined, among other interfaces, a public User-Network Interface (xe2x80x9cUNIxe2x80x9d), defined as the interface between an ATM user and a public ATM network; a private User-Network Interface, defined as the interface between an ATM user and a private ATM network; and, a Private Network-Network Interface (xe2x80x9cPNNIxe2x80x9d) defined as the network-network interface between two private networks or switching systems. Various features of ATM are enabled by signaling messages defined by these interfaces.
In view of the foregoing, it is readily surmised that the implementation of virtual private networks and ATM communications services is very hardware-dependent, with VPNs implementing many switching and communications platforms.
As in current VPN/ATM networks, a telecommunications Intelligent Network typically consists of one or more switching platforms integrated with one or more intelligent call processing platforms that contain sophisticated computer hardware and software components. These intelligent networks have evolved in parallel with piecemeal and proprietary advances in the communications and computing technology. As a result, today""s networks are built with products that are integrated into vendors"" proprietary platforms, and that are highly specialized to provide a certain set of functions. Thus, switching platforms are built on a vendor""s embedded processors and other hardware components that are under the control that vendor""s proprietary software. As Intelligent networks are built with a patchwork of incongruous hardware and software platforms that are each designed to support different services, many incompatibilities are introduced into the network infrastructure, making it increasingly difficult to deploy new services and integrate existing services. Consequently, network operators and service providers are faced with many obstacles in their attempts to offer new services. For example, to implement new services and features, the network operator must rely not only on a switch vendor""s proprietary switching hardware, but also on that switch vendor""s proprietary software to control switching. Thus, to develop its network infrastructure to support a new service, a network operator must incur the high costs of a switch vendor""s platform development. Moreover, the switch vendor process in developing and deploying new services may take an inordinate amount of time, which is completely undesirable in an industry in which speed to market is a critical factor in success.
Since the intelligent call processing services and features extant in current Intelligent Networks tend to rely on a particular vendor""s proprietary or specialized mechanisms embedded in the network infrastructure, new services often rely on vertical development efforts that are both costly and time-consuming. Network infrastructure that is developed to support one new service is simply not readily available or flexible enough to support the introduction or deployment other new services. Even the task of modifying or enhancing an existing service to provide new features becomes significant, often requiring extensive re-configuration of intelligent network infrastructure and involving the modification of source code in network processors, which can be intrusive to real-time call processing functions and resulting in network downtime.
One implication of a specialized network infrastructure for each service is that it becomes too costly to provide an advanced service everywhere in the network. As a result, calls must be routed to a specialized service node, prohibiting the optimization of network efficiency. The problem of a specialized network infrastructure for each intelligent service is especially exacerbated as different communications technologies are currently being integrated into hybrid networks. Intelligent network infrastructure that is built to provide services over one type of network, e.g., switched-circuit telephony, is not readily or easily adaptable to provide services over another type of network, e.g., packet-switched. If a network operator needs to provide a traditional telephone service over the Internet or an ATM network, a new intelligent network platform must be built. Even within the context of a switched-circuit telephony network, digital matrix switches from different vendors require different interfaces to, and different features within, the intelligent call processing system.
It would thus be highly desirable to provide an intelligent network infrastructure that supports all call and event processing and communications services and features for any type of switching network, and particularly an Intelligent Network for supporting ATM and VPN services.
The present invention is directed to an intelligent network implementing processes and apparatus for supporting ATM/Vnet services. Particularly, the intelligent network comprises the ability to receive an ATM VNET call, translate the dialed VNET number and then extend the call to a correct termination. Prior to the outdial, source address and subscription validation, destination address screening, source address screening and VNET number translation are performed. In one embodiment, it may be assumed that the VNET call is an ATM to ATM call requiring no number translation.
In placing Vnet/ATM calls, it is assumed that the network does all resource allocation, e.g., bandwidth reservation and allocation. The resource specification in the ATM setup message (e.g., bandwidth) is validated against the customer""s subscription versus the current network utilization.
Particularly, the intelligent network for performing Vnet Services includes a plurality of distributed service nodes, each node providing an execution environment that may provide all of the event processing functionality necessary to handle a call or event at the instance it is received at the resource complex, e.g., router, physically associated with that particular service node. The intelligent network is of a highly scalable architecture and engineered to ensure that telecommunications services, embodied as executable service logic programs (objects) capable of instantiation at each service node, are deployed in a cost-effective manner. The intelligent network additionally provides intelligent event processing services independent of and transparent to the switching platform or resource complex in which an event is received, and is readily adapted to handle call events. Thus, the dependency for expensive, vendor-specific hardware, operating systems and switching platforms, is eliminated. The distributed intelligent network additionally supports location-independent event processing service execution via a network operating system, enabling the modular software logic programs to be run virtually anywhere in the architecture, and provides location-independent communications among these distributed processes, thus eliminating the need for specialized service nodes.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.